1. Field of the Invention
The present invention relates to a three-dimensional shape determining apparatus and a three-dimensional shape determining method, and particularly it relates to a technique which is suitably used to obtain three-dimensional shape data of a subject (or an object) by projecting pattern light on the subject and imaging the projected pattern light.
2. Description of the Related Art
A three-dimensional shape determining method of obtaining three-dimensional shape data of a subject by projecting pattern light serving as a marker on the subject and then imaging the projected pattern light is a technique which has been well known.
Here, the important factor to achieve this technique is to image the projected pattern light and then accurately calculate the position of the marker in an image obtained by imaging the projected pattern.
For example, the principle of a technique called a complementary pattern projection method has been introduced in “Journal of Institute of Electronics, Information and Communication Engineers, D, Vol. J71-D, No. 7, pp. 1249-1257”. Besides, in a technique disclosed in Japanese Patent Application Laid-Open No. 2009-042015, the method same as above is used.
In the complementary pattern projection method, more specifically, two kinds of pattern lights which have bright and dark sections alternately inverted and by which complementary illumination distributions are formed on a surface of a subject are projected on the surface of the subject and an intersection point at which the bright and dark sections of these pattern lights intersect is used as a marker.
However, in the conventional method like this, in the case where the two kinds of pattern lights are projected and the projected pattern light is then imaged, if an intensity of ambient light (natural light) changes, there is a problem that an error may occur when the position of the marker is calculated.
The present invention, which has been completed in consideration of the above problem, aims to be able to accurately detect a point at which bright and dark sections of two kinds of pattern lights which were projected on a subject and in which the bright and dark sections thereof have been inverted intersect, even if ambient light changes.